This invention relates to a tube for dispensing two products simultaneously, and more specifically to a tube having two chambers formed from different materials.
A known means for dispensing two products simultaneously involves the use of dual chambers in a dispensing tube. As a typical example, U.S. Pat. No. 4,528,180 to Schaeffer discloses a tube with two chambers, each chamber containing one of the substances to be dispensed. As shown in FIG. 3A of that patent, each chamber is in communication with an orifice through which the substances are dispensed. The two chambers are separated by a divider in the middle of the tube, which is attached to the outside walls of the tube. Upon squeezing the tube, the walls of the tube collapse, creating a pressure within each of the chambers and thereby causing the substances housed in the chambers to be dispensed simultaneously. Alternatively, as shown in FIGS. 1 and 2 of that patent, two separate tubes may be secured together to dispense two substances.
U.S. Pat. No. 4,964,539 to Meuller discloses a tube with a plurality of chambers for dispensing two or more substances simultaneously. As in the Schaeffer patent, the chambers are separated by dividers that attach to the outside walls of the tube. Upon squeezing the tube, the flexible walls create a pressure within the chambers, simultaneously dispensing the substances in the chambers through orifices in communication with the chambers.
U.S. Pat. No. 3,866,800 to Schmitt discloses a non-pressurized package for dispensing two products. The package has bellowed chambers for allowing more uniform dispensing of product.
Other such dispensing tubes are known wherein the tube contains two or more chambers, each housing a substance to be dispensed through orifices in communication with the chambers, by squeezing the tube. In all of these known devices, however, the chambers are made from the same material, usually a polymer of some type.
In dual chamber tubes, the amount of material dispensed from each chamber is dependent upon the decrease in volume of the chamber occasioned by the deformation of the walls of the chamber. This deformation, and thus the amount of material dispensed, depends upon several factors including the viscosities of the substances to be dispensed, the size and shape of the orifices through which the substances are dispensed, the pressure applied to the tube, and the configuration of the tube and chambers.
As previously mentioned, in prior dual chamber tubes, the chambers are formed from a single material. Thus, both chambers will have the same properties relating to flexibility, longevity, and resistance to corrosive products, etc. However, this is not always desirable. Where the two materials to be dispensed have different properties, it may be desirable to vary the properties of the dispensing chambers individually.
As an example, two part tooth-cleansing preparations are becoming increasingly popular. Specifically, such preparations often include an oxidizing agent (such as hydrogen peroxide) and a foaming agent (such as baking soda), including coloring and flavoring agents. In such cases, the choice of a proper material for the packaging can be difficult. A material which acts as an oxygen barrier is desirable for the oxidizing agent, whereas a material with good flavor barrier properties is desirable for the flavored material. However, finding one material with all the desired properties may be difficult or impossible. More likely, it is just expensive.
Further, it may be desirable for the two chambers of a dual chamber dispensing tube to have different flex characteristics due to the properties of the materials being dispensed. If one material has a substantially lower viscosity than the other, the chamber containing the less viscous material should be stiffer. In this manner, more energy is taken up by the chamber and less is transferred to the task of pushing material out of the dispensing tube. In this way, the two material could be dispensed evenly, even though they had differing viscosities.
A dual chamber dispensing tube that facilitates application of proper pressure to both chambers and thereby enables a constant, steady flow of materials from each of the tube chambers is desirable.